SAFETY: If there’s any doubt at all, there’s no doubt

From Lex of neptunuslex.com

So, I’d asked for the day yesterday from my real job, one of 15 such being accorded to my annual station these days. On top of the federals. Mine being an hourly labor, with “paid time off.”
Spent half the day at work and the other half flying, four air combat demo sorties being my apportioned ration. The planes had already flown four times that morning before the afternoon shift rung in, and daylight was wasting.
With our guest pilots having been briefed, I ended up at the hold short in 50W, going through my pre-take off checklists with John in the trunk, a magnificently framed, blond headed farmer’s son turned tractor salesman. He was at least six four, and his shoulders were nearly half that width, with a broad, easy smile on his apple cheeked face that had no least hint of guile in it. It only took a bit of imagination to draw a beard on that face, some animal hides on his back and a Viking broad axe in his hand to render him a fearful (if imaginary) specter. I honestly don’t know how he poured himself in the cramped back seat of the tiny Varga, but he was sitting there, strapped in tightly and sporting a “oh, gosh” grin.
The magnetos were fine, but the carb heat check had to be done three times. On every other flight I’d ever flown the drop from 1800 RPM with carburetor heat selected had been a hundred RPM or so. Maybe two. But 50W dropped from 1800 RPM to around a grudging thousand or so, which was passing strange.
There’s no lower limit on the checklist for an RPM drop with carb heat on, but given that the airplane idles in flight at around a thousand RPM, the idea of losing 800 more in the landing pattern should carb heat be required was thought provoking. And yet there were all those young Midwesterners (and Canadians, too) all waiting for their turn at the donnybrook. The time line was taut to get it all done.
I thought about it again, which should have been a warning sign: If there’s any doubt at all, there’s no doubt. You’d always rather be on the ground wishing you were in the air than in the air wishing you were on the ground. But I get paid to fly these airplanes, not to break them. And if the airplane was hard down, it’d be me taking bread off my employer’s table.
My lead took the runway with both of us cleared for take-off, I toyed with the throttle a bit trying to come to some sort of decision as the traffic stacked up behind me - the SNJ, a Cirrus SR-22 and a beautiful little blue Champ. On the runway, I eased the throttle back to ground idle when it sputtered down to 750 RPM - a 250 RPM drop, and that with the mixture full rich. I began to feel that old “mission accomplishment” pressure kick in - it’s almost always self-imposed - the pressing need to get things done against a mulish resistance to doing it. Everybody wants you to go, but even more they want you to come back and if you don’t, it’s all on you old sport. Pilot in command, and that.
The symptoms said carburetor icing, but it was a warm, pleasant day with never a trace of visible moisture. The knowledge that adding carb heat would have caused the engine to sag even further put paid to the notion of breaking the surly bonds. My only engine was running rough on the deck, the hope that things might clear up once airborne was fond fantasy. Enough.
There was a palpable disappointment in the air as I taxied back to the flight line. The plane had already flown four flights, the clock was ticking and it isn’t all beer and skittles in the air touring business these days.
My passenger stepped out and joined a handful of his confreres, chatting thoughtfully and looking on with feigned insouciance as maintenance Jedi master Skip turned up with his wrench and went swiftly to work. I guess I sort of understand powerplants, and if you tell me what the problem is I get it immediately after you’ve told me. Skip’s the kind of man that gets it first - you tell him what you were seeing in the cockpit and the light just comes on, he knows. I’ve always admired that in a mechanic.
In short order he identified the flaw: The airscoop is attached below the carburetor and it tends to vibrate in the airflow, which over time can cause the hardware that encloses the carburetor bowl and float to shake loose a little. Eventually you get a secondary air source in the gap between the seals, which affects the fuel/air mixture adversely. Skip worked quickly but authoritatively under the engine with the cowlings all peeled back, and eventually - having tested the motor at various RPMs, mixture and carb heat settings - I was as certain as I could be that we would both be fine, your correspondent and his Viking passenger, who’s Minnesotan ma no doubt loved him dearly, and whose father loved him so much that he almost told him so, once.
I don’t know that my only engine would have quit shortly after take-off, plunging us into the densely populated departure end subdivision of Kearney Mesa . But neither was I sure it wouldn’t. The difference between the two was a matter of thirty minutes maintenance time.
It was a good flight, and a squeeker of a landing. Turning off the runway though I noticed that the right brake required a great deal more force than did its peer on the left to achieve proportionate response. Was it flyable? Yeah, I guess. But it wasn’t right, and it was with a heavy heart that I asked Skip to once again go to work while our paying passengers milled about, having first done the obvious and checked the break pads and rotor. I didn’t want to come off as a nancy boy with passengers to fly and the sun casting admiring glances at the western horizon, but you’re supposed to have two brakes.
It had been air in the brake lines, which took him a trifling amount of time to bleed. We flew the rest of the passengers in good time before the sun went down, shared a beer at the end of the day and put the airplanes to bed. Mine in better condition than I’d found it. That’s not nothing. I got the important things right.